title: Total brain white matter is a major determinant of IQ in adolescents born preterm.
abstract: OBJECTIVE
  In preterm infants, white matter (WM) abnormalities detected on magnetic resonance imaging (MRI) at term-age are associated with early developmental delay. We set out to study this association in adolescents born pre-term, by examining intellectual outcome in relation to markers of brain injury, focusing on the effects of WM reduction.
  
  
  METHODS
  Seventy-nine participants were recruited and assessed at a mean age of 16 years: 49 adolescents born preterm (<32 weeks' gestation) with a wide spectrum of brain injuries (including 22 with no identifiable brain injury at birth) and 30 term-born controls. Data collected included: brain MRI scans, full-scale intelligence quotient (IQ) scores, educational attainments, and behavioral scores. Measures of WM reduction included total volume, cross-sectional area of the corpus callosum (CC), and ventricular dilatation. Cerebellar volumes and neuroradiological ratings were also included.
  
  
  RESULTS
  WM volume and IQ were reduced in the preterm groups (both with and without brain injury). Total WM volume and CC area jointly explained 70% of IQ variance in the adolescents born preterm, irrespective of the presence or severity of brain abnormalities detected at birth or on follow-up MRI. This relationship was not seen in controls. Importantly, correlations were also found with real-world measures of academic achievement and behavioral difficulties.
  
  
  CONCLUSIONS
  Preterm birth has a long-term effect on cognition, behavior, and future academic success primarily as a consequence of global brain WM reduction. This emphasizes the need for early therapeutic efforts to prevent WM injury and promote or optimize its development in preterm neonates.
authors.affiliation: Institute of Child Health, University College London, London, United Kingdom.
authors.forename: Gemma B
authors.initials: GB
authors.lastname: Northam
authors.forename: Frédérique
authors.initials: F
authors.lastname: Liégeois
authors.forename: Wui K
authors.initials: WK
authors.lastname: Chong
authors.forename: John S
authors.initials: JS
authors.lastname: Wyatt
authors.forename: Torsten
authors.initials: T
authors.lastname: Baldeweg
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D061085:Agenesis of Corpus Callosum; D001921:Brain / Q000002:abnormalities*; D001930:Brain Injuries / Q000473:pathology / Q000523:psychology*; D002531:Cerebellum / Q000002:abnormalities* / Q000473:pathology; D002552:Cerebral Ventricles / Q000002:abnormalities* / Q000473:pathology; D003071:Cognition; D004108:Dilatation, Pathologic / Q000175:diagnosis; D004522:Educational Status; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007360:Intelligence; D007361:Intelligence Tests; D008279:Magnetic Resonance Imaging; D008297:Male; D009035:Mothers; D009929:Organ Size